Endophytic colonization of tomato plants by the entomopathogenic fungus Beauveria bassiana for controlling the South American tomato pinworm, Tuta absoluta

Abstract

Background: The deployment of entomopathogenic fungi (EPF) for the control of crop pests is an important alternative to synthetic pesticides. Despite recent advances in EPF formulations and application techniques, their efficacy is still limited by abiotic and biotic factors. Entomopathogenic fungi naturally colonize plant tissues or they can be artificially inoculated, protecting the plants from insect attack. Beauveria bassiana is the most widely used fungal biological control agent and has potential as an endophyte to protect a range of crops. Although B. bassiana is known to be pathogenic to the South American tomato pinworm, Tuta absoluta (Meyrick), this fungus could be more efficient when deployed as an endophyte to protect tomato plants from attack. Methods: Three B. bassiana isolates were screened for virulence against T. absoluta larvae by application of conidia to leaf surfaces. Following confirmation of virulence, tomato plants were then exposed to conidial suspensions using a forced uptake technique. Only one isolate, LPP139, colonized the leaves. Seedlings were then inoculated with LPP139 and the presence of the fungus in different plant tissues was monitored over 30 days. Possible effects of B. bassiana endophytic colonization on plant development were also evaluated. Following confirmation of endophytic colonization of leaf tissues, T. absoluta 2nd or 3rd instar larvae were offered leaves and survival was monitored over a 7-day period. Results: All three B. bassiana isolates were virulent to T. absoluta, with approximately 90% mortality over 10 days when conidia had been applied to leaf surfaces. Various plant inoculation techniques were tested but only seedling inoculation was successful. LPP139 successfully colonized all of the plant tissues. High percentages of colonization were observed in roots, stems and leaves up to 30 days after inoculation, with no negative effects on plant growth. When T. absoluta larvae were exposed to B. bassiana colonized leaves, survival was reduced to zero over a 7-day period. Conclusions: The endophytic colonization of tomato plants with EPF is a promising method of controlling the South American tomato pinworm. The fungus was detectable for up to 30 days, longer than has been previously observed

The endophytic fungi from South Sumatra (Indonesia) and their pathogenecity against the new invasive fall armyworm, Spodoptera frugiperda

“…Barra-Bucarei et al (2020) state that endophytic fungal isolates have the ability to have a systemic mode of action. The results of detection by Carolina et al (2020) show that the endophytic fungi can still be found in the roots, stems and leaves up to 30 days after inoculation. However, according to Shikano (2018), the endophytic fungi are able to colonize plant parts for several months and the duration of their persistence in the plant tissue varies depending on the age of the plant (high persistence in young tissues).…”

Effects of Myco-Entomopathogens on Bio-Control of Trialeurodes Vaporariorum, Endophytic Colonization of Tomato, and Compatibility with selected pesticides

“…These entomopathogenic fungal strains recovered from different parts of tomato plant tissues (roots, stems, and leaves) that con rmed their potential to move and establish throughout the plant parts. The entophytic colonization of tomato (Mwamburi, 2021;Silva et al, 2020), soybean (Russo et al, 2019), pecan (Ramakuwela et al, 2020), and coconut (Gaviria et al, 2020) have been achieved by both B. bassiana and M. anisopliae strains. This suggests that these entomopathogenic fungal isolates have the potential to colonize different plant species besides to tomatoes.…”

“…Tomato plant tissues have been naturally and arti cially colonized with entomopathogenic fungi and they can promote growth and protect plants from insect pests (Silva et al, 2020). According to (Barra-Bucarei et al, 2020), the endophytic B. bassiana has the potential to control T. vaporariorum and promote the growth of tomatoes.…”

A review of the management of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) with special reference to biological control using plant extracts

“…The most bacterial control agents used to manage T. absoluta is Bacillus thuringiensis, [29,30,31,32] and Saccharopolyspora spinosa [33] . Also, several entomopathogenic fungi are used in the control of tomato leaf miner: Metarhizium anisopliae [34,35] ; Beauveria bassiana [36,37,38] , Aspergillus oryzae [39] , Saria farinosa [40] , Clonostachys sp [38] and Purpureocillium lilacinum [40] . Nutrient exhaustion and toxicosis induced by fungi penetration leads to death of the insect [41] .…”